1. Field of the Invention
The present invention relates to an apparatus for precisely aligning electronic components on a printed circuit board (PCB) and a method for aligning electronic components using the same.
2. Description of the Related Art
A component mounting apparatus such as a chip mounter mounts a small-sized electronic component on a printed circuit board (PCB). The component mounting apparatus includes a suction unit for sucking and grabbing electronic components, a head unit for supporting, rotating and moving up and down the suction unit, and a transfer unit for moving the head unit in X-Y-direction.
In the operation of the component mounting apparatus, electronic components are picked up by the suction unit, and then the picked-up components are moved to a mounting position by the transfer unit. Subsequently, the electronic components are mounted on the PCB by rotating and moving up and down the suction unit.
In the process of mounting the electronic components, the electronic components must be precisely aligned in the mounting unit of the PCB. The alignment of components is performed using a vision system or optical diffraction.
In the vision system, images of electronic components are captured by a camera and the captured image is transferred to a computer. Also, the center point of the electronic component displayed on a monitor is compared to that of a predetermined template pattern, and then errors of X and Y coordinates and a rotation angle are detected to thereby correct the error, and then the components are mounted on the PCB. However, by the above-described method, components must be picked up by the suction unit to be moved to a region where the vision system is positioned.
Thus, a method for emitting light to electronic components picked up by an suction unit of a pickup device to directly detect an error of the electronic components is disclosed in U.S. Pat. No. 5,559,727. That is, a shadow of the component generated by emitting light to the side of the component is detected by a charge-coupled device (CCD). At this time, the width of the shadow of the component is changed according to rotation of electronic components, so that the change of the shadow width is detected to thereby detect a position and an angle of the component.
In the above-described method, light emitted to the side of the component must be parallel light to precisely detect the change of the shadow width of the component. Thus, the method requires a device to form parallel light, which makes the structure of the device complicated.
To solve the above problems, it is an object of the present invention to provide an apparatus for aligning components in which electronic components are picked up by a pickup device, and then the position and angle of the component are measured to precisely install the component, and a method for aligning components using the same.
Accordingly, to achieve the above object, the apparatus for aligning components includes a light source; a scattering plate for scattering light emitted from the light source towards the side of the component; a focus lens for focusing the scattered light having passed through the component; and a light detector for receiving the focused light from the focus lens to detect a side image of the component.
Here, the light source and the scattering plate are installed at one side of the component, and the focus lens and the light detector are installed in the other side of the component.
According to another embodiment of the present invention, the light source includes first and second light sources installed at one side of the component, the scattering plate includes a first scattering plate installed between the component and the first light source and a second scattering plate installed between the component and the second light source, and the focus lens and the light detector are aligned to be perpendicular to the first and the second light sources with respect to the component.
According to still another embodiment of the present invention, the light source, the scatter plate, the image formation lens and the light detector are aligned at one side of the component.
According to another aspect of the present invention, a method for aligning components includes the steps of: picking up electronic components; scattering light emitted from a light source by a scattering plate to proceed to the side of the component; and detecting a side image of the component which results from the scattered light and is focused by a lens.